linux-kernel - Re: [PATCH v2 1/1] Bluetooth: make hci_test

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <21570C6D-0C2F-40CA-9100-5A5CC7D1CEAB@holtmann.org>
Date:	Thu, 19 Feb 2015 08:10:28 -0800
From:	Marcel Holtmann <marcel@...tmann.org>
To:	Jiri Slaby <jslaby@...e.cz>
Cc:	Johan Hedberg <johan.hedberg@...il.com>,
	BlueZ development <linux-bluetooth@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"Gustavo F. Padovan" <gustavo@...ovan.org>
Subject: Re: [PATCH v2 1/1] Bluetooth: make hci_test_bit's addr const

Hi Jiri,

> gcc5 warns about passing a const array to hci_test_bit which takes a
> non-const pointer:
> net/bluetooth/hci_sock.c: In function ‘hci_sock_sendmsg’:
> net/bluetooth/hci_sock.c:955:8: warning: passing argument 2 of ‘hci_test_bit’ discards ‘const’ qualifier from pointer target type [-Wdiscarded-array-qualifiers]
>        &hci_sec_filter.ocf_mask[ogf])) &&
>        ^
> net/bluetooth/hci_sock.c:49:19: note: expected ‘void *’ but argument is of type ‘const __u32 (*)[4] {aka const unsigned int (*)[4]}’
> static inline int hci_test_bit(int nr, void *addr)
>                   ^
> 
> So make 'addr' 'const void *'.
> 
> [v2] make the pointer in the cast const too. 
> 
> Signed-off-by: Jiri Slaby <jslaby@...e.cz>
> Cc: Marcel Holtmann <marcel@...tmann.org>
> Cc: Gustavo Padovan <gustavo@...ovan.org>
> Cc: Johan Hedberg <johan.hedberg@...il.com>
> ---
> net/bluetooth/hci_sock.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
> index 1d65c5be7c82..d1a7d67619d8 100644
> --- a/net/bluetooth/hci_sock.c
> +++ b/net/bluetooth/hci_sock.c
> @@ -46,9 +46,9 @@ struct hci_pinfo {
> 	unsigned short    channel;
> };
> 
> -static inline int hci_test_bit(int nr, void *addr)
> +static inline int hci_test_bit(int nr, const void *addr)
> {
> -	return *((__u32 *) addr + (nr >> 5)) & ((__u32) 1 << (nr & 31));
> +	return *((const __u32 *) addr + (nr >> 5)) & ((__u32) 1 << (nr & 31));
> }

we had a lengthy discussion about this before. I am reluctant to change any of this until we have a test tool that proofs this does not break userspace API compatibility.

I don't see how just adding const would break anything, but I cautious since this code is pretty much a big mistake that we are carrying around for almost 14 years now.

Regards

Marcel

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/